My daughter has multiple food intolerances, so I find vegan recipes very suitable for her (although I do still need to do some tweeking). I note that the vegan butter has soy, which is something she cannot have. She eats Nuttelex butter (which is all vegetable based) - would this substitute work well? Thanks

So if your daughter isn't allergic to any of these ingredients you should be good to go. If you're feeling particularly adventurous, you could always make Regular Vegan Butterhttp://veganbaking.net/fats/vegan-butters/735-vegan-butter
But instead of using soy milk, use hemp milk or even almond milk.